Noise-damping device for powerdriven typewriters



June 7, 1938.

A. SAL'Z'BERGER NOISE DAMPING DEVICE FOR POWER DRIVEN TYPEWRITERS FiledFeb. 17, 1957 HHHHIIIH.

Inventor- A-nczrezs s aZzZQrgB/ IHHHHII.

Afforneys Patented June 7, 193 8 NOISE-DAMPING DEVICE FOR- POWER- IDRIVEN TYPEWBIITEBS Andreas Salzberger, Eriurt, Germany, assignor toOlympia Biiromaschinen-werke A. G Erfnrt, Gel-mam Application February'17, 1931, Serial No. 126,283 In Germany February 21, 1936 7 Claims.

This invention relates to power-driven typewriting machineswithnoise-dampenedimpression of the kind described in my U. S. LettersPatent No. 2,059,537, in whichthe type-levers are positive- 1y actuatedby the intermediary of an eccentric and in which the thus actuatedtypelever when having arrived in the proximity ofitsupperdeadcentreposition is engaged by a rotary pressingon member which transmitsadditional power to it and presses it with correspondingly increased,force against the platen or paper roller.

In order to attain with type-writing machines of the above kind anincreased writing speed, it is indispensably requisite that theco-operation of the type-lever lifting device with the pressingon devicebe unobjectionable and take place without the generation of noise. Inother words, the

type-lever and all members oscillating together,

with it must be accelerated positively and gradually, without beingthrown or flung at the commencement of its lifting movement, and thismovement must be gradually retarded towards the end, so that no blowproper is produced when the type contacts with the paper-on the platenand the additional pressing-on of the type upon the paper takes place inthe proper moment.

In the above mentioned patent type-levers and intermediate levers ofusual design are used,

these members being coupled with one another,

by means of joints comprising pins and slots in which thepins areguided, the entire system being actuated by a lever provided with aroller held against an eccentric by means of a spring.

I Springs are, however, no reliable members in 3 a type-writing'machineand-are only adapted to prevent flinging under certain conditions. Be-

sides, at the return motion of the rods and links these members are notin all cases taken along with the driving members concerned, and the 40joint pins guided in slots, as already mentioned,

are subject to undesired additional accelerations which partly causedisturbances and, apart from diflicult adapting work, give rise torattling noises especially at a higher writing speed.

45 Now, the-above mentioned drawbacks and disadvantages of the knownmechanism dealt with in the preceding paragraphs are obviated in and bymy present invention, the chief characteristic feature of which is thatthe race path of the cc- 5,, centric co-operates with an oscillatablemember provided at its opposite ends with small blocks or, maybe, smallrolls bearing on said race path, said oscillatable member being indriving connection with an intermediate lever connected with the itype-lever by toothed segments, of which one is provided at thetype-lever, and the other at the 1 free end of said intermediate lever.

This arrangement does not onlypresent the advantage that the drivingpower is not loaded at all with the springs hitherto necessary for the 5return movement of the levers, but it is, besides, now rendered possibleto make use of only one size of the mentioned intermediate levers, asall their supporting points can lie concentrically with re: spect to thecircularly arranged supporting points of the type-levers. It is to beunderstood that toothed type-levers and toothed intermediate levers areknown per se.

Concerning the noise-dampening another improvement resides therein thatanother member is likewise able to contact elastically with the racepath of the eccentric is co-ordinated to one of the first-mentionedblocks or rolls, the object of said other member being to compensatesmall diflerences of distance and it is preferably hinged to so thecircularly curved oscillatable member and is. arranged ahead of theblock or roll at the adjacent end of this member in such a manner thatit imparts to the eccentric an additional rotary movement when theeccentric is in an approxig5 mate dead-centre position.

The invention is illustrated diagrammatically and by way of example onthe accompanying drawing of which Fig. 1 is a side view oi the en.- tiremechanism concerned, and Fig. 2 is a side view showing a modification. V

On the drawing, i denotes the type-lever which is provided at its rearend with a circularly curved toothed sector la, the teeth 0! which lieconcentrically with respect to the fulcrum 2 of said lever. Said sectorla meshes with another toothed circular sector 30. provided at the freeend of an intermediate lever 3' and lying concentrically with respect tothe fulcrum 3b of this lever.

4 denotes the eccentric disc to which is turnably attached at one of itssides the known catch-pawl 5 which is moved into operative position bymeans, of a pawl I attached to the free end of the keylever 6, and bytwo double-armed intermediate levers 8 and 9. These members (1, 8, 9)and their manner of operationare known, for which reason I abstain fromentering into details concerning them. In the drawing the parts hithertomentioned are shown in their position of rest.

As regards now the transmission of motion from the eccentric 4 to thetype-lever l, (at the type end of which is visible a particularly shapedcurved, downwardly directed projection lb intended ior co-oneration witha specially provided 56 stance a small roll I! which bears on thecircumferential race path of said eccentric. Illa denotes the upper legof this lever, Hlb the lower one. The leg Illa of the lever I0 isjointed at I to one end oi a link l3, the-other end of which is hingedto the toothed segment 3a of the intermediate lever 3, whereby the leverI0 is connected also with the key-lever l by the intermediaryof the twotoothed sectors, as appears clearly from the drawing.

The outer circumference of the eccentric disc I is not accuratelycircular, but its shape is, anyhow, such that the width between therolls I2 is always the same. 3

As has already been mentioned, small pivoted blocks l 9, Fig. 2, may beused instead of the small rolls l2, but irrespective of whether rolls orblocks are employed, there arises, especially if the writing speed iscomparatively high, a rattling noise owing to the continual change ofdirection as soon asthe distance between the rolls or blocks and theeccentric varies even only very slightly. I obviate said noise in mypresent improved mechanism by the following contrivance:

The pivot H which connects the link I3 with the leg Illa of .thedouble-armed lever Ill supports also a double-armed lever l5 whichcarries at one arm a race-roll I l 8 bearing likewise on thecircumferential race path of the eccentric 4, and being at its other endconnected with one end of a helical tensile spring H, the other end ofwhich is attached to an arm I00 forming part of the lever l0 so that theroll I6 is pressedagainst the eccentric. Thereby the lower roll I! is.also pressed against the eccentric and,-owing to the co-operation ofthe two upper rolls, the lever I0 is completely prevented from makingjerky movements if there eventually should arise a small diflerencebetween the diameter of the eccentric and the-distance between the rollsII.

An important feature resides, finally, in that the additional roll I6 isnot arranged at a side of the adjacent roll l2, but ahead of the same asregards the direction of rotation of the eccentric, in consequencewhereof the roll l6 tends to turn the eccentric in clockwise directionabout its axis l8 when the eccentric is in its lower dead-pointposition, as in the drawing. Owing to this action, the eccentric issecured in place when it is in its position of rest, that is to say, theinterengaging hooks of the pawls 5 and 8 are firmly pressed against oneanother, but instantly after the pawl 9 has been released by adepression of the keylever B the rotary motion of the eccentric is'initiated.

The mechanism canbe designed to operate particularly noiselessly bysubstituting turnable or oscillatable blocks IQ for the rolls H, as hasalready been mentioned, but in such a case it is requisite to lubricatethe circumferential race of the eccentric.

It must be mentioned that the eccentricdisc 4 and the double lever (III)are provided with grooves or holes or the like on as many places aspossible to,avoid unnecessary swing-masses.

I claim:-- 1. A mechanism for obtaining noise-dampened imprints of thetype-levers of a power-driven type-writing machine, comprising incombination .with the type-levers a power-driven rotating desaidoscillating member is pivotally arranged and pivoted blocks are providedat the ends of said member engaging said eccentric disc.

3. A mechanism as specified in claim 1 in which a second member isprovided pivotally arranged on said first member, the one end of whichyieldingly engages the eccentric disc:

' 4. A mechanism for obtaining noise-dampened imprints of thetype-levers of a power-driven type-writing machine comprising, incombination with the type-levers, a power-driven rotating device adaptedto lift the selected type-lever and comprising a shaft, an .eccentricdisc and. means adapted to couple saidshaft with said disc, an

oscillating-member engaging said eccentric disc.

on opposite points, an intermediate lever pivotmediate lever with saidtype-lever to eifect-a contemporaneous swinging movement and a secondoscillating member pivoted on said first mentioned one and yieldinglyengaging said eccentric disc.

5. A mechanism as specified in claim4 in which the point of engagementof the said second member with the eccentric disc is arranged ahead ofthe adjacent point of contact of the said first oscillating member.

6. A mechanism as specified in claim 4 in which rolls are provided onthe ends of said members engaging the eccentric disc.

7. A mechanism as specified in claim 4 in which the point of engagementof the said second member with the eccentric disc is arranged ahead ofthe adjacent point of contact of the said first oscillating member insuch a manner that said second member tends to turn the eccentric discwhen the latter is near to its dead-point position.

ANDREAS SALZBERGER.

, ally arranged and connected with said oscillating member. meansadapted to couple said inter--

